They claim it’s the biggest engine advance since the jet. The British firm, called Reaction, is developing an engine that would allow an aircraft to operate like a normal plane in the Earth’s atmosphere, and then a rocket when in space. The technology could mean flights to any point on Earth in a maximum four hours, and potentially the world’s first reusable space plane.

One key component they’ve already built is a heat exchanger able to cool air from 1,000 degrees Celsius to -150 degrees in one-hundredth of a second. The firm is now looking to raise $400 million to fund the next phase of development. They hope to have an engine ready for sale within a decade.